Examines a sample of seven aircraft airframe cost models: three RAND models published sequentially from 1966 to 1976; one developed by Planning Research Corporation in 1965 and revised in 1967; two from J. Watson Noah Associates (1973 and 1977); and a transport aircraft model from Science Applications, Inc. (1977). The intent is to determine whether the model output is reasonable over a broad range of inputs, what limitations should be noted, and where one model might be preferable to the others. The critique shows that all the models have some deficiencies and all should be used with caution. The more recent models appear to be better than the older ones, which may be taken as a sign of progress, but it is plain that more progress is needed. Some of the lessons learned in this review may be helpful in pointing out how the next generation of aircraft airframe cost models could be improved.